Presently, in the fields of pharmacy and medicine, prolonged or sustained medicators have as their primary goal the delivery of a beneficial agent at a constant rate over an extended period of time. However, many therapeutic programs require the dose of medication administered to a warm-blooded animal comprise rate-programmed intervals for extended time periods. For example, the Ferring Zyklomat pump was designed to deliver gonadotropin-releasing hormone (GnRH) in a pulsatile regimen as the physiological pattern in primates as disclosed in a paper presented at the Robert First Conference, Oct. 7 and 8, 1985, Philadelphia, PA. The therapeutic value of drug rate-programmed intervals was reported for bleomycin free-intervals in cancer therapy in Cancer Treat. Rep. Vol. 62, pp. 2011 to 2017, 1980. The pharmacokinetics of interval doses by intravenous infusion of gentamicin in subtotal nephrectomized dogs was reported in Toxicol. Appl. Pharmacol. Vol. 75, pp. 496 to 509, 1984. Also, in antibiotic therapy, and in desensitizing against allergens, it is desirable to provide a therapeutic program consisting of a single dose of the drug followed by a delayed dose of drug for optimum therapy. Thus, it is evident from the above presentation a need exists for programmable delivery system that can provide the desired time profile of drug administration to achieve the intended and beneficial effect.